GREAT WHITE MYSTERY 97
part of the California hub, at just 120 or so.
Are these large numbers or small? Are great
whites thriving or dwindling? The world has
about 4,000 tigers and 25,000 African lions.
Using the lowest estimates, global great white
numbers resemble the estimate for tigers, an
endangered species. Using the highest estimate,
the population is closer to that of the lions, which
are classified as vulnerable. Several experts see
them heading toward extinction; others see a
positive trend. Some say rising seal populations
are a sign that great whites are nearly gone, while
others say more seals mean more sharks. Aaron
MacNeil, an Australian statistician who crunch-
es shark data, says the appearance of sharks
around Cape Cod and the increased activity in
the Southern Hemisphere suggest the latter. “I
haven’t seen any evidence in the last decade that
white sharks are declining,” says MacNeil. “ Yes,
there is a historical depletion of white sharks.
But the story is not that they are going extinct.
The story is that they are probably increasing
very, very slowly.”
There’s reason to be hopeful. Few if any fish-
ermen target great whites today, yet a global
pact, the Convention on International Trade
in Endangered Species, gives white sharks its
second strongest conservation rating because
fishermen catch them unintentionally. With
numbers so low, even accidental catches can
play havoc with the species, which, as a top
predator, has an ecologically important role in
managing the oceans.
To understand whether great white sharks
need our protection, we must know not only how
many there are but also where they go. Their
migrations aren’t neat, like a bird’s or a butter-
fly’s. They’re messy, with one hugging the coast
while another zigzags hundreds of miles out to
sea. Many, but not all, seem to seasonally move
between warm and cold water. And the paths
seem different for males, females, and juveniles.
Today, with long-term, long-distance tags
that can communicate via satellite, scientists
are finally getting some clarity. For years sci-
entists have noticed that adult great whites in
California and Mexico quit the coast in late fall.
Now we know where they go: deep water in the
middle of the Pacific Ocean. Why they visit this
great white shark “café” remains unclear. “I call
it Burning Man for white sharks,” says Salvador
Jorgensen, a biologist who studies factors that
drive great white migration and ecology. “They
are heading out to what some people call the
desert of the ocean, and what the hell are they
doing out there?”
One possible answer is mating, which might
explain why no one has ever observed it. The
area is roughly the size of California and thou-
sands of feet deep, which makes it hard to
monitor sharks there. But satellite tags tell us
that the females swim predictable straight pat-
terns while the males swim up and down in the
water column, possibly searching for mates.